Well...some discoveries have been worth it. They have helped in medicine and in certain conveniences. But many discoveries have led to technologies that have created problems.
Point is that we should know when to stop. The quest for knowledge can become an obsession, giving us a high and a false sense of control and power.
All scientific knowledge is tentative and we are never going to know it all. Even what we think we know could change.
The principle of diminishing returns works in scientific discoveries as much as anywhere else.